Journal of magnetic resonance imaging : JMRI
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J Magn Reson Imaging · Jul 2006
Comparing real-world advantages for the clinical neuroradiologist between a high field (3 T), a phased array (1.5 T) vs. a single-channel 1.5-T MR system.
To evaluate signal-to-noise ratio (SNR) and neuroradiologists' subjective assessments of image quality in 3-Tesla (3-T) or phased-array MR systems that are now available for clinical neuroimaging. ⋯ Both quantitatively and qualitatively, the phased-array system provided image quality superior to that of the 1.5-T and 3-T single-channel systems.
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J Magn Reson Imaging · Jul 2006
Effect of using local arterial input functions on cerebral blood flow estimation.
To investigate a previously developed method for perfusion-weighted MRI (PWI) cerebral blood flow (CBF) estimation that uses local arterial input functions (AIFs) in stroke patients, and determine its ability to correct delay and/or dispersion (D/D) errors. ⋯ The local-AIF technique results in an increase in the calculated CBF values for tissues with D/D, consistent with a reduction in the errors associated with D/D.
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J Magn Reson Imaging · Jul 2006
Manipulation of image intensity distribution at 7.0 T: passive RF shimming and focusing with dielectric materials.
To investigate the effects of high dielectric material padding on RF field distribution in the human head at 7.0 T, and demonstrate the feasibility and effectiveness of RF passive shimming and focusing with such an approach. ⋯ The image intensity distribution in the human head at ultra-high field strengths can be effectively manipulated with high permittivity padding. Utilizing this effect, the B(1) field inside the human head of a given RF coil can be adjusted to reduce the B(1) field inhomogeneity artifact associated with the wave behavior (RF passive shimming) or to locally enhance the signal-to-noise ratio (SNR) in targeted regions of interest (ROIs; RF field focusing).
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J Magn Reson Imaging · Jul 2006
Free-breathing delayed hyperenhanced imaging of the myocardium: a clinical application of real-time navigator echo imaging.
To compare a free-breathing (FB) acquisition with the current standard of breath-holding (BH) in a clinical setting using identical two-dimensional MR pulse sequences for imaging of myocardial delayed hyperenhancement. ⋯ An FB navigator echo acquisition can be effectively used in the setting of myocardial delay hyperenhanced imaging. Image quality is similar or superior to that of BH imaging.
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J Magn Reson Imaging · Jul 2006
Phase contrast MR imaging to measure changes in collateral blood flow after stenting of recurrent aortic coarctation: initial experience.
To assess the feasibility of using phase contrast magnetic resonance (PC-MR) imaging to measure the change in collateral blood flow early after stenting of aortic coarctation. ⋯ PC-MR can be used to measure changes in collateral circulation after stent treatment of coarctation of the aorta.